Bit drills shoe to total depth in one run in the North Sea

Petrofac provides drilling management services to NEO Energy for the Leverett conventional oil field in the UK Central North Sea. Following challenges with other drill bits, Petrofac switched to the EnduroBlade 360™ rolling diamond element bit. As a result, the 12¼-in section was successfully drilled in a single run from the casing shoe to total depth, achieving 8,387 ft at 76.1 ft/h and surpassing the 40-ft/h target. This high ROP saved both significant time and costs for Petrofac.

The objective was to drill the 12¼-in section in the Leverett oil field within the agreed authorization for expenditure (AFE). In consideration of the abrasive environment, the goals were to avoid sluggish ROP, high stick-slip, and a typical bit trip due to low ROP.

As the industry's only rolling element that actually cuts rock, the EnduroBlade 360 rolling diamond element bit drilled the 12¼-in section to total depth in a single run, achieving 8,387 ft at 76.1 ft/h vs. the 40-ft/h target. Because of the improved wear resistance of the drill bit, the ROP was higher than the historical offset performance, resulting in reduced drilling time and fewer drillbit runs. This achievement exceeded the operator’s expectations and came under the AFE with all directional objectives achieved.

Leveraging the DBOS™ drillbit optimization system, compressive strength plots were used to pinpoint areas of significant compressive strength changes. These changes, such as transitions from soft to hard formations, are crucial to highlight zones where cutting structure damage could occur during drilling operations. Additionally, the i-DRILL™ integrated dynamic system analysis service was combined with the IDEAS™ integrated dynamic design and analysis platform, along with the DBOS system, to formulate a predrill drillers’ road map for the key formation scenarios that were deemed to pose the greatest risk. This road map eliminated guesswork by providing precise starting points for operating parameters for each of these depths.